Biotech stocks Bluebird Bio Inc. and Spark Therapeutics Inc. were in the spotlight Monday as analysts weighed in on data presented by both companies along with others attending the American Society of Hematology annual meeting in Atlanta.

The company and partner Celgene Corp.
CELG, +0.80%
said a Phase I trial of their bb2121 anti-B-cell maturation antigen (BCMA) CAR T cell therapy in patients with multiple myeloma found that 94% achieved an objective response, 89% achieved a very good partial response, 56% achieved a complete response and 9 out of 10 who were evaluable for minimal residual disease, or MRD, were MRD-negative, after a median follow-up of 40 weeks after treatment. Patients with MRD are those that have fewer than 5% of cancer cells in the bone marrow at the time of CAR therapy.

Patients in the trial had undergone at least seven other treatments, including a stem-cell transplant, before they were given bb2121.

Goldman Sachs raised its 12-month share-price target to $309 from $186 on the news in a note titled ”The sky’s the limit,” and said the therapy “looks to have a disruptive impact on the multiple myeloma (MM) treatment paradigm” given the solid efficacy and safety profile, which supports development of this ‘potentially curative approach.’ ”

Bluebird also offered data suggesting its LentiGlobin is on the path to becoming a key treatment for severe sickle cell disease, an inherited red blood cell disorder, said Goldman.

Canaccord Genuity analyst John Newman raised his share-price target to $228 and said he estimates a 75% probability of approval for bb2121, up from a prior estimate of 50%.

Evercore analyst Josh Schimmer took a more cautious tone, applauding the data but cautioning that investors are taking a victory lap “well before evolving competitive dynamics are fully appreciated” or a sustainable business model is established.

“The results in both multiple myeloma and sickle cell / beta thal are exciting—but largely predictable and continue to reinforce our view that competitive players will also yield predictable results,” Schimmer wrote in a note. “ There is intense competition emerging (especially in CAR-T) and barriers to entry may be minimal while the speed of innovation only increases.”

Celgene shares rose 2% on the news.

It was a different story for Spark Therapeutics
ONCE, +4.87%
, whose stock tumbled more than 40% in volume that was more than 17 times the daily average, after the company reported data from trials of a hemophilia treatment that analysts said look less competitive than a rival product from BioMarin Pharmaceutical Inc.
BMRN, +0.41%
.

Hemophilia is an inherited disease that affects males and stops their blood from clotting normally. The condition can cause life-threatening episodes of external and internal bleeding and requires regular injections of plasma-derived human Factor IX.

The company presented early data from a trial of its SPK-8011 in hemophilia A involving five patients, but the results disappointed analysts.

“Although the enrollment size is small so far (n=5), early signs raise more caution than encouragement, on balance, and lead us to question whether there will be adequate dose-response for patients to reliably achieve normal Factor VIII expression levels,” Leerink analysts wrote in an early note.

RBC analysts agreed that given the small patient numbers, “the data raise more questions than answers,” but said the variability in Factor VIII results were below their expectations.

Spark is scheduled to host an investor event at 12.30 p.m. Eastern Monday.

Other movers: Juno Therapeutics Inc.
JUNO, +0.00%
was down 12%, after an update of results from an early-stage trial of a treatment for aggressive lymphoma showed three-month complete remission rates were slightly lower than earlier data.

UniQure N.V. shares
QURE, +2.31%
rose, then edged lower, after the company reported positive results in an early-stage trial of a treatment for hemophilia B. The company said eighteen-month follow-up data from a Phase I/II trial of AMT-060 in the second-dose cohort found “substantial improvement” in disease state in all five patients, and that all those who previous required frequent infusions were able to stop them.

The iShares Nasdaq Biotech ETF
IBB, +0.56%
was up 0.5%, and has gained 20.5% in 2017, while the S&P 500
SPX, +0.64%
has gained 18% and the Dow Jones Industrial Average
DJIA, +0.45%
has gained 23%.

Intraday Data provided by SIX Financial Information and subject to terms of use. Historical and current end-of-day data provided by SIX Financial Information. All quotes are in local exchange time. Real-time last sale data for U.S. stock quotes reflect trades reported through Nasdaq only. Intraday data delayed at least 15 minutes or per exchange requirements.